regression reporter: remove / update bisection reports selectively

**As a regression reporter, I want to stop be able to disable some bisection reports or to update them to show a different status so I don't get redundant or confusing bisection reports.**

## Background

Currently, there are bisection reports are re-sent even if the related regression was already fixed. In this case the bisection should be (automatically, if possible) removed or updated to reflect the situation accurately and clearly. Alternatively, or complementary, it should be possible for a user to edit the current status of a bisection report.

The issue names no files, tests, or entry points. Start by locating the regression reporter and bisection-report lifecycle, then clarify whether reports should be removed automatically, updated, or made manually editable. Done means redundant reports are prevented or their status is represented accurately.

Written by the indexing model from the issue text.